Data communication networks exchange user data between User Equipment (UE) like phones, computers, and machine transceivers. The user data might be audio/video, email, web content, software, or data files. The UEs execute software applications to generate and consume this user data. The UEs and the data communication networks use the Internet Protocol (IP) to transfer their user data.
IP networks use IP addresses and IP ports to route IP packets between UEs. For various reasons, these IP addresses and IP ports may be modified in transit. For example, a network gateway may translate the IP addresses and ports used inside its network to hide them from the public. In another example, a wireless relay may assign IP ports on the relay's IP address to attached UEs. Network Address and Port Translation (NAPT) is a general term for these type of tasks.
Quality-of-Service (QoS) for data communications entails characteristics like bit rate, latency, priority, and the like. Various techniques for delivering data QoS have been developed. Some IP networks mark IP packets with QoS indicators. Virtual Private Networks (VPNs) may deliver IP QoS by IP address and port over a closed and controlled IP network. Unfortunately, the use of IP addresses and ports to deliver QoS is often frustrated by the many NAPT modifications. Thus, some IP networks deliver data QoS over the underlying layer 2 data tunnels. A prime example are wireless IP networks where a wireless relay and a network gateway both perform NAPT tasks and QoS is delivered over layer 2.
The Port Control Protocol (PCP) allows IP hosts (including UEs) to manage their NAPT data in the NAPT devices. For example, a UE may add, modify, and delete its NAPT translations in a network gateway by using PCP messages. Unfortunately, PCP does not have the functionality efficiently deliver data QoS. Moreover, PCP does not effectively facilitate QoS in a NAPT scenario with a cascade of IP address and port translations.